Fast Facts: Eastern Blue Groper

  • Despite the name, the Eastern Blue Groper is not a groper, but a wrasse.
  • It lives in shallow coastal waters and is regularly seen around exposed reefs.
  • It has peg-like teeth, heavy scales, a large tail and thick lips.
  • Juveniles are brown to green brown. Juveniles are all female.
  • As the fish matures, it goes through an initial phase (IP) during which the fish could be either male or female.
  • Adult females are brown to reddish-brown.
  • Blue Grouper are hermaphrodites – females generally change into males at around 50 cm in length, although the timing of this change can be influenced by environmental and social factors.
  • Adult males are bright blue, hence the common name. The blue can range from deep navy to cobalt blue, and there may also be darker or yellow-orange spots or lines around the eyes. By this stage, these fish have reached the terminal phase.
  • Although the blue form is often male and the red form female, research has shown this is not always the case.
  • Adults are found in a wide range of habitats from shallow waters, down to 40 m.
  • Juveniles are usually found in estuarine seagrass beds.
  • The Eastern Blue Groper can grow to over a meter in length and a weight of 25 kg.
  • Although its growth has not been studied in detail, it is likely they are long-lived and relatively slow growing.
  • In NSW, the quantity of Eastern Blue Gropers, were significantly depleted by fishing and a five-year fishing closure was imposed between 1969 and 1973.
  • In 1974, commercial fishing and recreational angling were permitted again, but the ban on spearfishing was continued.
  • In 1980, the commercial sale of Eastern Blue Groper was prohibited and since then, the species has been restricted solely to capture by recreational line fishing.
  • There’s a minimum legal fishing length of 30 cm and a bag limit of 2 fish, with a maximum of 1 fish over 60 cm.
  • Are not permitted to be taken by commercial fishers.
  • Are endemic to Australia.
  • It is particularly well known to scuba divers in New South Wales and was made the fish emblem for New South Wales in 1996.
  • It is a carnivorous species, often seen eating sea urchins.
  • Adults are found on rocky coastal reefs.
  • They spawn during the winter (July-October).
  • The young live primarily in estuarine sea grass beds during winter.
  • The species presents no danger to humans.
  • The Eastern Blue Groper is very friendly to humans and often approach divers, freedivers and snorkellers.
  • Fish in general, cover themselves in a layer of sticky mucus that traps microbes and contains antimicrobial chemicals.
  • If a groper is patted or rubbed, some of their protective coating to fight off infections may be temporarily compromised.
  • It was once common practice for many divers to feed urchins to Eastern Blue Gropers. This practice is not encouraged, as we are only visitors underwater and as such should only be observing this amazing world and not altering it in ways we do not understand.

References: australian.museum; dpi.nsw.gov.au; personal experience; sciencefocus.com; and underwater.com.au.

Published by Karina Teuma

karinateuma.com Karina Teuma is a Passionate Marine Biology Enthusiast, Environmentalist, Snorkeller, Freediver, Scuba Diver and more.

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